int sum(struct TreeNode* root, int i)
{
	if (root == NULL)
	{
		return 0;
	}
	if (root->left == root->right && i == 1)
		return root->val;
	return sum(root->left, 1) + sum(root->right, 2);
}
int sumOfLeftLeaves(struct TreeNode* root) {
	// write code here
	return sum(root, 0);
}